Changes in Tillering, Nutritional Status, and Biomass Yield of Panicum Maximum Used for Cadmium Phytoextraction

Although several grasses have been evaluated for cadmium (Cd) phytoextraction, there are no studies assessing how Cd is accumulated and distributed in the tissues of Panicum maximum grown in mildly polluted soils. The evaluation of tillering, nutritional status and biomass yield of this grass, mainly along successive shoot regrowths, is not well studied so far. Thus, P. maximum Jacq. cv. Massai was grown for two periods in an Oxisol presenting bioavailable Cd concentrations varying from 0.04 (control) to 10.91 mg kg−1 soil. Biomass yield of leaves and stems´ growth have decreased under the highest Cd exposure, but it did not occur in the regrowth period, indicating that Cd-induced toxicity is stronger in the early stages of development of P. maximum. The tillering was not compromised even the basal node presenting Cd concentrations higher than 100 mg kg−1 DW. We identified a restriction on Cd transport upwards from basal node, which was the main local of Cd accumulation. Apparently, P, K, Mg, S and Cu are involved in processes that restrict Cd translocation and confer high tolerance to Cd in P. maximum. The Cd-induced nutritional disorders did not negatively correlate with factors used to calculate phytoextraction efficiency. However, the nutritional adjustments of P. maximum to cope with Cd stress restricted the upward Cd transport, which decreased the phytoextraction efficiency from the available Cd concentration of 5.93 mg kg−1 soil.

Nutritional comparison between hydroponically grown leguminous and non-leguminous fodder to identify the adaptability and best harvesting time for sustainable hydroponic grass production

Two types of fodder crops were evaluated in this study, maize (Zia maize) and black gram (BG) (Vigna mungo) and in maize, non-descriptive local maize (LM) and hybrid maize (HM) verity were used. LM was considered as control and changes of the nutritional composition according to the type of fodder (leguminous and non-leguminous) and the day was evaluated. For comparative nutritional analysis, dry matter (DM), crude protein (CP), ether extract (EE), crude fibre (CF), acid detergent fibre (ADF), neutral detergent fibre (NDF), and total ash were analyzed and the biomass yield was measured using weight balance and root and shoot length of experimental fodders. Results revealed that among three types of forages total DM was significantly (P<0.01) higher in HM and significantly (P<0.01) lower in BG. Considering total CP and NDF, it was significantly (P<0.01) higher in BG and HM than LM. The highest biomass yield and shoot length were observed in BG and the lowest biomass yield was observed in HM. Moreover, with the increment of days, all fodder sprouts DM% was constantly decreasing, however, CP% maintained the same level from day 1 to 5. Although from day 6 to 9, CP% increased moderately for HM and BG, CP% decreased slightly for LM. Therefore, farmer can use BG and HM for maximum utilization of nutrients and considering DM and CP% for LM day 6 was the best time for harvesting; however, for HM and BG, day 9 or more than 9 was the best time for harvesting. Res. Agric., Livest. Fish.8(3): 321-328, December 2021

Media engineering in marine diatom Phaeodactylum tricornutum employing cost-effective substrates for sustainable production of high value renewables

Phaeodactylum tricornutum is a marine diatom, and well-studied model of unicellular microalga. This diatom contains a wide range of high-value renewables (HVRs) with high commercial relevance owing to their importance in human nutrition and health. In this study, we screened P. tricornutum for biomass, eicosapentaenoic acid (EPA) and fucoxanthin production under photoautotrophic and mixotrophic condition with various substrate combinations. Results highlights that culture supplemented with glycerol and urea lead to enhanced biomass, biochemical and HVR production. Further continuous feeding of urea in glycerol supplemented medium results in an increase in biomass yield (0.77 g L-1) by ~ 2-fold. Additionally, continuous feeding of urea channelizes the carbon flux towards biosynthesis of fatty acids increasing FAME content by ~2-fold as compared to the control conditions. Overall EPA and fucoxanthin production was 27 mg L-1 and 11 mg L-1 (~2 & 4 fold) in urea fed cultures respectively. Present study demonstrates efficient valorization of cost-effective substrates such as glycerol and urea for the production of high-value renewables in P. tricornutum.

Optimization of Propagation Medium for Enhanced Polyhydroxyalkanoate Production by Pseudomonas oleovorans

Polyhydroxyalkanoates (PHAs) represent a promising alternative to commercially used petroleum-based plastics. Pseudomonas oleovorans is a natural producer of medium-chain-length PHA (mcl-PHA) under cultivation conditions with nitrogen limitation and carbon excess. Two-step cultivation appears to be an efficient but more expensive method of PHA production. Therefore, the aim of this work was to prepare a minimal synthetic medium for maximum biomass yield and to optimize selected independent variables by response surface methodology (RSM). The highest biomass yield (1.71 ± 0.04 g/L) was achieved in the optimized medium containing 8.4 g/L glucose, 5.7 g/L sodium ammonium phosphate and 35.4 mM phosphate buffer. Under these conditions, both carbon and nitrogen sources were completely consumed after 48 h of the cultivation and the biomass yield was 1.7-fold higher than in the conventional medium recommended by the literature. This approach demonstrates the possibility of using two-stage PHA cultivation to obtain the maximum amount of biomass and PHA.

Productivity of switchgrass (Panicum virgatum L.) agrophytocenoses for long-term use

Purpose. To determene the productivity of switchgrass (Panicum virgatum L.) agrophytocenoses under the long-term use. Methods. Field, statistical, calculation and comparative. Results. During long-term switchgrass cultivation, the lowest yield was obtained in the first vegetation year: 19.7 t/ha in the control treatment, 25.3 and 17.5 t/ha in the experimental treatments. The average raw biomass yield was as following: 30.3 t/ha in the control (variety ‘Cave-in-Rock’), 32.6 t/ha and 26.5 t/ha in the experimental treatments (varieties ‘Kanlow’ and ‘Morozko’, respectively). The yield of solid biofuel (17.3 t/ha) indicates the advantage of ‘Kanlow’ over the control (11.7 t/ha). The lowest yield (15.7 t/ha) was obtained from ‘Morozko’ variety. The energy yield over the treatments: 312.8 GJ/ha in the control, 397.5 and 367.2 GJ/ha in the experimental treatments, respectively. The cost of the grown production was as following: 416.03 UAH/t in the control (‘Cave-in-Rock’), 312.01 UAH/t in ‘Kanlow’, and 366.42 UAH/t in ‘Morozko’. The profitability of the control (‘Cave-in-Rock’) was 69.5%, ‘Kanlow’ – 101.4%, ‘Morozko’ – 66.8%. Economic evaluation of the productivity of switchgrass agrophytocenoses resulted in the following ranking: ‘Kanlow’, ‘Cave-in-Rock’, ‘Morozko’. When analyzing the energy equivalent of switchgrass biomass production and energy consumption, it was found that ‘Kanlow’ yielded 588.8 GJ/ha and the control – 468.3 GJ/ha, which is lower by 120.5 GJ/ha. Conclusions. The yield of switchgrass agrophytocenoses on average over the years of research (2014–2019) was 30.3 t/ha in ‘Cave-in-Rock’ (the control), 32.6 t/ha in ‘Kanlow’, and 26.5 t/ha in ‘Morozko’. The energy equivalent of the obtained yield was 468.3 GJ/ha in ‘Cave-in-Rock’ and 588.8 GJ/ha in ‘Kanlow’, which is by 120.5 GJ/ha higher than in the control.

Optimization of Chlorella Culture Conditions with Response Surface Methodology to Increase Biomass

Microalgae is gaining popularity as a major ingredient in nutrition supplements. To mass cultivate, it is imperative to improve the biomass yield hence optimization of cultures conditions becomes paramount. In this work, an attempt has been made to optimize the microalgal production using response surface methodology (RSM) and validate further the optimized parameters. The optimum conditions for the cultivation of Chlorella sp. KPU016 under optimized nutrient conditions were pH 8.2, the light intensity of 3100 lx, glycerol 1.44 g.L-1 (under pre-set conditions of 12 h lighting, the temperature at 27±1°C. With these RSM-driven optimum conditions, the yield of microalgal biomass achieved was 282.50 mg.L-1. For larger-scale microalgal harvesting, the validated optimal conditions can be inferred as the best for enhanced microalgal production. The isolate was partially sequenced and submitted to the NCBI database and the GenBank accession number is MZ348364.

Effect of biochar blended organic fertilizers on soil fertility, radish productivity and farm income in Nepal

Declining soil fertility and nutrient availability are one of the major threats to reducing crop productivity in Nepal. A field experiment was conducted to assess the potential of biochar (10 t ha-1) blended with organic and inorganic fertilizers on improving soil fertility and radish productivity in Morang district, Nepal. Biochar was prepared from locally available twigs, branches, and wood using the soil pit “Kon tiki” method. The experiment was laid out in Randomized Complete Block Design with 7 treatments having four replications viz., control (CK), biochar (BC), biochar + cattle manure (CM), biochar + poultry manure (PM), biochar + cattle urine (CU), biochar + commercial biofertilizers (BF) and biochar + inorganic fertilizers (urea-N). The nitrogen rate used in all the treatments was equivalent to 100 kg ha-1. The agronomic effect of biochar blended organic amendments was compared with control and inorganic urea-N treatments. Biochar amended plots showed significantly higher soil pH (6.5), organic matter (4%), total N% (0.8%), available P (80.1 kg ha-1), and K (203.6 kg ha-1) compared with control. CM increased marketable yield by 320% (63 t ha-1) and biomass yield by 198% (100 t ha-1) compared with control (15.0 t ha-1 and 34 t ha-1) of marketable and biomass yield, respectively. CM increased marketable yield by 44% compared with the urea-N treatment (44 t ha-1). Moreover, net return was observed highest with CM treatment among all the organic and urea-N treatments. The study suggests that the combination of biochar with locally produced cattle manure has the potential to increase radish productivity and could compete with mineral nitrogen fertilizers while producing similar or even higher crop yields and economic returns.